The present invention relates to a transmission system applied to transmission and relaying of sending right request signal between a plurality of communication equipment connected in the form of a loop.
In LANs (Local Area Networks) or various private control equipment etc., there has been employed a transmission system described below which has been already proposed as the Japanese patent application No. 260800/84 assigned to the same applicant as the present application. According to this transmission system, a plurality of communication equipment which perform transmission and reception of data are interconnected by means of a loop transmission path, whereupon the transmission direction of a data signal is determined in advance. During transmission by any communication equipment which has acquired or possessed the sending right, other communication equipments relay a signal received from one side of the transmission path to the other side of the transmission path. When newly possessing the sending right in response to the completion of the transmission, the communication equipment which requests for the sending right adds a code indicating the priority level of the sending right to a sending right request signal generally called a "Token" and transmits the code added signal. Thus, the communication equipment which has the highest priority level among the entire communication equipments will acquire the sending right.
In the prior art, however, the decision as to whether each communication equipment should relay and transmit a received signal or should receive the received signal by itself and the decision as to whether when receiving the sending right request signal, each communication equipment should acquire the sending right by itself or should relay and transmit the sending right without possessing it are conducted after all signals have been received. Accordingly, when the received signal should be relayed and transmitted, a predetermined time required until such decisions are established is added per each communication equipment. This results in the problem that delay time required for decision is increased, particularly when the sending right request signal is transmitted.